Common Name: OCONEE BURROWING CRAYFISH
Scientific Name: Cambarus (Depressicambarus) truncatus Hobbs
Other Commonly Used Names: none
Previously Used Scientific Names: none
Family: Cambaridae
Rarity Ranks: G1G2/S2
State Legal Status: Threatened
Federal Legal Status: none
Description: The overall color of the Oconee burrowing crayfish is pale to bright
orange. The areola is virtually non-existent and the rostrum is short and broad. The
abdomen is obviously narrower than the cephalothorax and the claws may be robust. This
species reaches a maximum total body length of about 75 mm (3 inches).
Similar Species: No other bright orange crayfish occurs in Georgia.
Habitat: Complex burrows adjacent to streams or in low areas where the water table is
near the surface of the ground.
Life History: Burrowing crayfishes inhabit a system of tunnels that may be very
complex with several openings to the surface. Openings to the tunnels are often marked
by piles of dirt or mud pellets (chimneys). Depending on the soil type and moisture
content, these chimneys can reach heights of 15 cm (6 inches) or more. These crayfishes
are typically confined to their burrows, but a male must leave its burrow to search for
females during the reproductive season. As mentioned above, they may also forage near
the opening of their burrow. Active burrows with fresh soil are seen from late spring to
late fall, particularly after rain events. During the dry part of the summer, burrow
openings may be plugged to help conserve moisture in the burrow. Reproduction
probably occurs during the spring and fall, but males in reproductive condition may be
found at any time during the year. It is very rare to find more than one adult crayfish in
the same burrow. When a female crayfish releases her eggs, she attaches them to her
swimmerets and is said to be “in berry.” Upon hatching, the juvenile crayfish are attached
to the mother by a thread. After the juveniles molt for the second time, they are free of
the mother, but stay close and will hold on to her for some time. Multiple juveniles are
occasionally found in a single burrow. Eventually they move off on their own. Crayfishes
molt 6 or 7 times during their first year of life and most are probably able to reproduce by
the end of that year. They molt once or twice a year for the remainder of their lives.
Although it is difficult to study burrowing crayfishes, some researchers believe they may
live as long as 10 years. Almost nothing is known about the life history of the Oconee
burrowing crayfish. Males in reproductive condition have been collected in April.
Survey Recommendations: Burrowing crayfishes may be collected by direct excavation
of their burrows, by trapping, and during night surveys. Excavating burrows is time
consuming and can be very difficult. It also results in destruction of the animals’ burrow.
Traps made with PVC pipes or mist nets can be effective. Burrowing crayfishes are
sometimes captured around the openings of their burrows on damp nights. Active
burrows are found from about mid-March to mid-November if the water table is within
about 2 feet of the surface of the ground.
Range: The Oconee burrowing crayfish is currently known from 11 locations in the
Oconee River system in middle Georgia. All of these locations are in the Coastal Plain
physiographic province.
Threats: The small range of this species makes it vulnerable to land disturbing activities
around streams and wetlands.
Georgia Conservation Status: One population occurs on the Beaver Dam Wildlife
Management area, which is currently managed by the Georgia Department of Natural
Resources.
Conservation and Management Recommendations: Areas with burrows should be
protected from land disturbing activities. Additional surveys and life history studies are
needed to better define the range of the Oconee burrowing crayfish and help predict its
response to environmental change. Environmental education programs should include
information about burrowing crayfishes and encourage protection of burrows.
Selected References:
Hobbs, H. H., Jr. 1981. The crayfishes of Georgia. Smithsonian Contributions to
Zoology 318:1-549.
Hobbs, H. H., Jr. 1989. An illustrated checklist of the American crayfishes (Decapoda:
Astacidae, Cambaridae, and Parastacidae). Smithsonian Contributions to
Zoology 480:1-236
Taylor, C. A., G. A. Schuster, J. E. Cooper, R. J. DiStefano, A. G. Eversole, P. Hamr,
H. H. Hobbs III, H. W. Robison, C. E. Skelton, and R. F. Thoma. 2007. A
reassessment of the conservation status of crayfishes of the United States and
Canada after 10+ years of increased awareness. Fisheries 32(8): 72-389.
Author of Species Account: Christopher E. Skelton
Date Compiled or Updated: June 2008